Cut the potatoes into thin slices and clean the mushrooms by gently brushing them, if necessary, rinsing them quickly under running water.
Spread an even layer of ricotta on the piadina, then create a layer of potatoes and top with mushrooms. Season with a drizzle of oil, salt and pepper and add clumps of fresh rosemary.
Cuocere in forno con funzione grill a 180°C per circa 15 minuti, fino a doratura.